The present invention relates to an apparatus for everting a flexible tube liner into the interior of a hollow tubular conduit, such as a previously existing underground sewer pipe.
One of the more successful pipe repair or rehabilitation processes which is currently used is described in Wood, U.S Pat. No. 4,064,211. Wood, U.S. Pat. No. 4,385,885 discloses apparatus useful in installing a liner according to the process described in U.S. Pat. No. 4,064,211, and briefly mentions, but does not describe, a lip seal, used in conjunction with a pair of controlled rollers to feed a liner into a conduit that is to be repaired. Various other sealing devices have been disclosed for use in connection with using fluid under pressure to evert a liner and extend it into a conduit to be repaired, as shown, for example, in Alexander, Jr., U.S. Pat. Nos. 5,597,353 and 4,942,183, Long, Jr., U.S. Pat. No. 5,358,359, Driver, et al., U.S. Pat. Nos. 5,154,936 and Re. 35,944.
Other apparatus for use in installing and everting a liner, as disclosed in Long, Jr., U.S. Pat. Nos. 4,668,125 and 4,685,983, has been quite large, and has avoided the use of a seal to maintain pressure within a portion of an apparatus by instead using a relatively tall column of water to provide the necessary fluid pressure within the liner being everted. Such apparatus has been undesirably unwieldy and expensive.
What is desired, then, is to provide a conveniently small and inexpensive apparatus useful to evert and install a flexible tubular liner into a conduit quickly and efficiently.
The present invention supplies an answer to the aforementioned need for a relatively small and inexpensive apparatus for use in installing a flexible tubular liner in a conduit, by providing a sealing inlet port for admitting a liner in the form of a flattened flexible tube into a pressurized chamber of an apparatus for everting and extending such a flexible tube into position for use to repair or line a conduit. The apparatus includes a container for holding air or another fluid under pressure to act on the flexible tube. The sealing inlet port is provided in the container to allow the liner to enter the container in a flattened configuration without significant loss of pressure, so that the pressure of the fluid in the container can be used to evert and extend the tubular liner into the required position within a conduit.
The sealing inlet port in one embodiment of the invention includes a base defining an elongate narrow mouth, and a pair of associated lips extend for a distance from the base, facing each other. In use of the sealing port, fluid under pressure surrounding the lips urges the lips together and against an object such as the flattened flexible tube passing through the sealing inlet port, to seal the inlet port yet allow the flexible tube to slide between the lips.
In a preferred embodiment of the invention the sealing inlet port can provide a sealing effect while permitting a rope, a lay-flat hose, a strap, or a cable to slide between the lips.
In a preferred embodiment of the sealing inlet port an elongate support member is fastened to each of the lips to keep them in the necessary positions and prevent them from being expressed from within the container of fluid under pressure.
In one embodiment such elongate support members are urged apart from each other, urging respective portions of the lips apart from each other to limit friction between the lips and the flattened liner tube.
In accordance with the invention the lips provide a sealing closure around the flattened tube being everted, but the lips are short enough and are supported sufficiently by the support members that the friction between the lips and the tube is small enough so that the pressure in the container, urging the lips toward each other and the tube, is sufficient to cause the tube to extend and be everted to a desired length.
In one embodiment of the invention a cover plate provides support for the base to which the lips are attached, and associated shutters provide a slot having an adjustable size extending through the cover plate.
In one preferred embodiment of the invention the apparatus includes a liner everter box having the sealing inlet port at its top end and including an outfeed opening at its bottom end, through which the flexible liner tube can proceed out from the liner everter box.
In one preferred embodiment of the invention a clamp associated with the outfeed opening from the liner everter box includes a conical inner clamping surface surrounded by a circular outer clamping seat or rim, together with linkages holding the two together to grip an end portion of a flexible tube between the conical inner clamping face and the surrounding clamping rim.
In one preferred embodiment of the invention a support frame holds the liner everter box in an appropriate position so that an everted liner extending from the outfeed opening can be directed conveniently to the appropriate position to enter into a conduit needing to be repaired.
In one embodiment of the invention the support frame includes adjustable legs, adjustable wheeled struts, and a mounting arm adapted to be received in a trailer hitch receiver on a motor vehicle.
In another preferred embodiment of the invention a pair of guide rollers are mounted on the support frame above the liner everter box.